#15 indi-sx patch to fix compilation with GCC 6

[Christian Dersch]

For compilation with GCC 6.x we need to include math.h, otherwise abs() function is not defined. See https://gcc.gnu.org/gcc-6/porting_to.html for more details. Patch in attachment, already applied in Fedora package.

[Hans Lambermont]

Anyone an idea how I can help getting this patch accepted ?

[Jasem Mutlaq]

Patch applied, thanks!